Spinal volumetric trabecular bone mass in acromegalic patients: a longitudinal study

Objective  Data on trabecular bone mass in acromegaly are controversial. All the studies are cross-sectional and bone mineral density (BMD) has been evaluated largely by dual X-ray absorptiometry (DXA), which is influenced by bone enlargement. In this study we assessed in acromegalic patients the effects overtime of GH excess on trabecular bone mass measured by single-energy quantitative computed tomography (QCT) which is not influenced by bone size.
Design  Longitudinal retrospective study.
Patients  A total of 46 acromegalic patients followed-up for 48 months (median), subdivided into four groups: group A (eugonadal patients with active disease: n  = 13), group B (hypogonadal patients with active disease; n  = 9), group C (eugonadal patients with controlled disease; n  = 10), group D (hypogonadal patients with controlled disease; n  = 14).
Measurements  Serum GH and IGF-I levels, spinal trabecular BMD, and vertebral fractures were evaluated in all patients. BMD variations were reported as change (Δ) in Z -values (Z-QCT) measured at baseline and end of follow-up per year (Δ Z-QCT).
Results  Δ Z-QCT was greater in group A vs. group B and D ( P = 0·002 and P  = 0·0001, respectively) and in group C vs. group D ( P = 0·009). Multivariate regression analysis showed that hypogonadal status (β = –0·69; P  = 0·001) and baseline duration of hypogonadism (β = 0·44; P  = 0·02) but not baseline duration of acromegaly, length of follow-up and disease activity, were significantly associated with Δ Z-QCT.
Conclusions  This longitudinal study suggests that the effect of chronic GH excess on spinal trabecular bone mass seems to be anabolic in active eugonadal patients but not in hypogonadal ones.     

Effect of aromatizable and unaromatizable androgen replacement in hypogonadal men on GH responsiveness

Objectives  Although studies have clearly demonstrated that oestrogen replacement affects GH responsiveness by causing relative GH resistance, the effect of androgen replacement is unknown. Circumstantial evidence only suggests that androgen replacement may increase GH sensitivity and/or responsiveness. To examine the impact of androgens on GH responsiveness, hypogonadal men underwent the IGF-1 generation test in the unreplaced state, replaced with testosterone (T) and also replaced with dihydrotestosterone (DHT), its nonaromatizable metabolite.
Design and patients  Twelve hypogonadal men with a normal GH axis were recruited. Each subject in random order had 4 weeks off T (NoRx), 4 weeks on T gel (TG) and 4 weeks on DHT gel (DHTG) applied daily, with 1 week washout between each preparation. An IGF-1 generation test using a subcutaneous injection of 7 mg of GH was performed at the end of each of these 4-week phases.
Measurements  Serum GHBP, total and free IGF-1, IGFBP-3 and acid-labile subunit (ALS) levels were measured at baseline and 24 h (peak) after GH administration.
Results  Despite a decrease in GHBP during the TG and DHTG phases, there were no observed differences in baseline, peak or increment (peak – baseline) total or free IGF-1 between the NoRx, TG or DHTG phases.
Conclusions  There is no evidence of fluctuation in GH responsiveness in hypogonadal men, untreated or replaced with T or DHT alone. This implies that the increased level of oestradiol as a consequence of T replacement in hypogonadal men does not impact significantly on GH responsiveness, nor is there evidence of an androgen effect with elevated DHT levels as a consequence of either T or DHT replacement.     

Effect of GH and/or testosterone deficiency on the prostate: an ultrasonographic and endocrine study in GH-deficient adult patients

BACKGROUND: The role of IGF-I in prostate development is currently under thorough investigation since it has been claimed that IGF-I is a positive predictor of prostate cancer. OBJECTIVE: To investigate the effect of chronic GH and IGF-I deficiency alone or associated with testosterone deficiency on prostate pathophysiology in a series of patients with hypopituitarism. DESIGN: Pituitary, androgen and prostate hormonal assessments and transrectal prostate ultrasonography (TRUS) were performed in 30 men with adulthood onset GH deficiency (GHD) and 30 age-matched healthy controls, free from previous or concomitant prostate disorders. RESULTS: Plasma IGF-I levels were significantly lower in GHD patients than in controls (Pearson's coefficient P<0.0001). At study entry, 6 of the 13 hypogonadal patients and 7 of the 17 eugonadal patients had plasma IGF-I below the age-adjusted normal range. At study entry, testosterone levels were low in 13 patients (mean +/-s.e.m., 3.8+/-1.0 nmol/l) while they were normal in the remaining 17 (19.4+/-1.4 nmol/l). No difference in prostate-specific antigen (PSA), and PSA density was found between GHD patients (either hypo- or eugonadal) and controls, while free PSA levels were significantly higher in eugonadal GHD than in controls (0.4+/-0.04 vs 0.2+/-0.03 microg/l; P<0.01). No difference in antero-posterior prostate diameter and transitional zone volume (TZV) was observed among groups, while both transverse and cranio-caudal diameters were significantly lower in hypogonadal (P<0.01) and eugonadal GHD patients (P<0.05) than in controls. Prostate volume (PV) was significantly lower in hypogonadal GHD patients (18.2+/-3.0 ml) and eugonadal GHD patients (22.3+/-1.6 ml), than in controls (25.7+/-1.4, P<0.05). The prevalence of prostate hyperplasia (PV>30 ml) was significantly lower in hypogonadal and eugonadal GHD patients, without any difference between them (15.3% and 5.8%), than in controls (43.3%) (chi(2)=6.90, P=0.005). No difference was found in PV between patients with normal or deficient IGF-I levels both in the hypogonadal group (19. 9+/-4.7 vs 17.3+/-4.0 ml) and in the eugonadal group (22.6+/-2.3 vs 21.8+/-2.5 ml). When controls and patients were divided according to age (<60 years and >60 years), PV was significantly lower in hypogonadal GHD patients aged below 60 years than in age-matched controls (P<0.01) or eugonadal GHD patients (P<0.01), without any difference between controls and eugonadal GHD patients. Controls aged above 60 years had significantly higher PV than both hypogonadal and eugonadal GHD patients (P<0.01). Calcifications, cysts or nodules were found in 56.7% of patients and in 50% of controls (chi(2)=0.067, P=0.79). In controls, but not in GHD patients, PV and TZV were correlated with age (r=0.82, r=0.46, P<0. 0001 and P<0.01 respectively). PV was also correlated with GH (r=-0. 52, P=0.0026), IGF-I (r=-0.62, P=0.0002) and IGF-binding protein 3 (IGFBP-3) levels (r=-0.39, P=0.032) but neither with testosterone or dihydrotestosterone (DHT) levels. In GHD patients TZV but not PV was correlated with age (r=0.58, P=0.0007) and neither TZV nor PV were correlated with GH, IGF-I or IGFBP-3 levels. CONCLUSIONS: Chronic GH deficiency in adulthood causes a decrease in prostate size, mostly in patients with concomitant androgen deficiency and age below 60 years, without significant changes in the prevalence of structural prostate abnormalities.     

Testosterone stimulates extra-hepatic but not hepatic fat oxidation (Fox): comparison of oral and transdermal testosterone administration in hypopituitary men

Background  Fat mass is increased in hypogonadal men and the changes are reversed by testosterone replacement. Testosterone administration enhances whole body fat oxidation (Fox). Fat is oxidized in the liver and in extra-hepatic tissues.
Objective  To determine whether the stimulation of Fox by testosterone arises primarily from the liver or from extra-hepatic tissues.
Design/patients  This was an open-label cross-over study. Thirteen men with hypopituitarism (age 53·1 ± 4·1 years) with both growth hormone (GH) and testosterone deficiency were studied sequentially after 2 weeks of treatment with transdermal testosterone (5 mg), no treatment, and stepwise incremental doses of oral crystalline testosterone (10, 20, 40 and 80 mg) in the absence of GH replacement.
Measurements  Serum testosterone, IGF-I, metabolic effects [resting energy expenditure (REE) and Fox], SHBG, and thyroid binding globulin (TBG) as markers of excessive hepatic androgen exposure, were measured at the end of each treatment period.
Results  When compared to the no-treatment phase, mean blood testosterone levels rose into the physiological range after transdermal testosterone delivery but did not significantly change after 10, 20, 40 or 80 mg oral testosterone treatment. Blood SHBG and TBG fell significantly with 80 mg oral testosterone dose but were unaffected by any other testosterone treatment. Fox increased significantly with transdermal but not with any dose of oral testosterone. Mean plasma IGF-I and REE were unaffected by testosterone, regardless of the route or dose.
Conclusions  Short-term testosterone administration does not stimulate hepatic fat oxidation but enhances whole body fat oxidation by acting on extra-hepatic tissues.     

The use of thyroid function tests in the diagnosis of hypopituitarism: definition and evaluation of the TSH Index

Background  TSH secretion in hypopituitary patients may be decreased due to TSH deficiency but it also remains under feedback inhibition by free thyroxine (fT4). We propose a TSH index (TSHI), as 'fT4-adjusted TSH', that corrects for any physiological TSH suppression, to provide a true estimate of pituitary thyrotroph function and any pathological pituitary suppression.
Methods  A total of 9519 thyroid function tests (TFTs) (Bayer Immuno-1^®) in 4064 patients of our institution were examined, including 444 patients investigated for hypopituitarism. Based on the physiological log-linear relationship between fT4 and TSH, we estimated the amount of feedback-induced change in log TSH per change in fT4, which allowed the extrapolation of log TSH to a fixed fT4 of 0, defining the TSHI. TSHIs were compared with other measures of pituitary function.
Results  Feedback inhibition was estimated to cause a 0·1345 decrease in log TSH (mU/l) for 1 pmol/l increase in fT4 concentration, therefore TSHI = log TSH + 0·1345 × fT4. Patients with lower peak-stimulated GH and cortisol concentrations had a significantly lower TSHI ( P <  0·0001). TSHIs measured before pituitary stimulation tests predicted highly significantly the risk of test failure ( P =  0·0002). Of all potential fT4–TSH combinations within the current reference ranges, 21·9% were identified as abnormal on the basis of the TSHI.
Conclusion  The TSHI provides an accurate estimate of the severity of pituitary dysfunction in hypopituitary patients based on simple TFTs. It predicts the probability of pituitary stimulation test failure and extends the diagnosis of TSH deficiency into areas of the normal TFT reference ranges.     

Testosterone substitution of hypogonadal men prevents the age-dependent increases in body mass index, body fat and leptin seen in healthy ageing men: results of a cross-sectional study

INTRODUCTION: In healthy men, body weight and total fat content increase with advancing age, while serum testosterone levels decrease. In order to elucidate whether a causal relationship between these phenomena exists, we investigated the influence of testosterone or human chorionic gonadotrophin substitution on body mass index (BMI), total fat mass and serum leptin in testosterone-treated and untreated hypogonadal patients in comparison with ageing eugonadal men. METHODS: In a cross-sectional study, the inter-relationships of body weight, total fat mass, serum sex hormones and leptin were analysed in untreated hypogonadal men (n=24; age 19-65 years), treated hypogonadal men (n=61; age 20-67 years) and healthy eugonadal men (n=60; age 24-78 years). Total fat mass was assessed by bioimpedance measurement. Univariate and multiple linear regression analysis was used to detect possible differences. RESULTS: In eugonadal men, serum testosterone levels decreased with advancing age (correlation coefficients: r=-0.71; P<0.0001), while BMI (r=0.39; P=0.002), total fat content (r=0.51; P<0.0001) and leptin (r=0.48; P<0.0001) increased significantly. In untreated hypogonadal patients, an increase in BMI (r=0.50; P=0.013) and total fat mass (r=0.41; P=0.044) was also observed with advancing age. However, in substituted hypogonadal patients, no age-dependent change in BMI (r=0.067; P=0.606), body fat content (r=-0.083; P=0.522), serum testosterone (r=-0,071; P=0.59) or serum leptin (r=-0.23; P=0.176) was found. CONCLUSION: Since testosterone-substituted older hypogonadal men show BMI and fat mass similar to those of younger eugonadal men and since non-treated hypogonadal men are similar to normal ageing men, testosterone appears to be an important factor contributing to these changes. Thus ageing men should benefit from testosterone substitution as far as body composition is concerned.     

Bone density and turnover in young adult patients with growth hormone deficiency after 2-year growth hormone replacement according with gender

GH deficiency (GHD) in adults is accompanied by reduced bone mass that may revert only after 2 yr of GH replacement. However, it is unclear whether the gender may modify bone responsiveness to GH replacement in adults. In this study we have evaluated whether bone mineral density (BMD) and turnover improve after GH replacement according to patients' gender. BMD at lumbar spine (LS) and femoral neck (FN), serum osteocalcin (OC), and urinary cross-linked N-telopeptides of type I collagen (Ntx) were assessed in 64 hypopituitaric patients (35 men, 30-50 yr) before and 2 yr after the beginning of GH replacement. Values of IGF-I and BMD at LS and at FN were expressed as Zscores. At study entry, IGF-I and BMD resulted similar among men and women with GHD. During GH replacement, IGF-I levels increased in both men and women without any difference in the percentage of IGF-I increase between the genders (p=0.47). In women receiving estrogen replacement, however, the percentage of IGF-I increase (p<0.05), and the Z IGF-I score (p<0.001) were significant lower than estrogen untreated women, although IGF-I levels were similar in the 2 groups (p=0.53). The GH dose adjusted for body weight required to restore normal age- and sex- matched IGF-I levels was lower in men than in women (p<0.001), and was higher in women receiving than in those not receiving estrogen replacement (p<0.05). In contrast, hypogonadal men treated with testosterone and eugonadal men received a similar GH dose (p=0.97). Also OC, Ntx levels, lumbar and femoral BMD improved (p<0.001) in all patients. Nevertheless, a greater increase in lumbar BMD increase was observed in men than in women (8.0+/-2.1 vs 2.6+/-0.4%; p<0.05). No significant difference was revealed in bone parameters in women treated or untreated with estrogen replacement and in men treated or not with testosterone replacement for concomitant hypogonadism. At the multiple correlation analysis, gender was a stronger predictor for the required GH dose than the age (p<0.001 and p=0.02, respectively). In conclusion, a 2-yr GH replacement normalizes IGF-I levels, increases bone mass and improves bone turnover both in men and in women with GHD without any difference between the 2 groups, provided that the dose of GH was modulated on the basis of IGF-I levels. Women receiving oral estrogens should receive a GH dose approximately doubled, as compared to men and women not receiving oral estrogens, to achieve similar effects on bone density and turnover. In particular, GH replacement dose, to be successful on bone mass and turnover, depends on gender in hypopituitary patients aged below 50 yr.     

Gonadal status and body mass index jointly determine growth hormone (GH)-releasing hormone/GH-releasing peptide synergy in healthy men

CONTEXT: Sex steroid hormones potentiate whereas increased body mass index (BMI) represses GH secretion. Whether sex steroids modify the negative effect of BMI on secretagogue-induced GH secretion in men is not known. The issue is important in designing GH-stimulation regimens that are relatively insensitive to both gonadal status and adiposity. OBJECTIVE: Our objective was to compare the relationships between BMI and peptide-stimulated GH secretion in men with normal and reduced testosterone and estradiol availability. SETTING: The study was performed at an academic medical center. SUBJECTS: Healthy young men were included in the study. INTERVENTIONS: Randomized separate-day iv infusion of saline and/or maximally effective doses of L-arginine/GHRH, L-arginine/GH-releasing peptide (GHRP)-2, and GHRH/GHRP-2 in eugonadal (n=12) and experimentally hypogonadal (n=10) men was performed. OUTCOMES: Regression of paired secretagogue-induced GH responses on BMI was determined. RESULTS: In eugonadal men, peak GH concentrations correlated negatively with BMI. In particular, BMI accounted for only 38% of the response variability after L-arginine/GHRH (P=0.0165), but 62% after GHRH/GHRP-2 (P=0.0012) and 65% after L-arginine/GHRP-2 (P=0.00075). In contrast, in hypogonadal men, GH responses were uncorrelated with BMI. The negative effects of BMI on peak GH responses in eugonadal and hypogonadal states differed most markedly after stimulation with GHRH/GHRP-2 (P=0.0019). This contrast was corroborated using integrated GH responses (P=0.0007). CONCLUSIONS: Short-term experimental gonadal sex hormone depletion attenuates dual secretagogue-stimulated GH secretion in lean young men. The inhibitory effect of relative adiposity on GH secretion appears to predominate over that of acute sex steroid withdrawal.     

GH receptor d3 polymorphism in Dutch patients with MPHD and IGHD born small or appropriate for gestational age

Objective  GH acts through the GH receptor (GHR). The GHR gene contains a genetic polymorphism caused by a deletion of exon 3 ( d3 ), with high frequency in the normal population. There is a continuing controversy whether the presence or absence of the exon 3 deletion ( d3+ vs. d3– ) affects the effect of GH in human growth.
Design, patients and measurements  For 144 patients with idiopathic isolated GH deficiency (IGHD, n  = 72) or multiple pituitary hormone deficiency (MPHD, n  = 72), amplification of the region around exon 3 of the GHR gene was performed. Clinical data and response to GH treatment were compared between GHR d3+ and d3– IGHD and MPHD patients born either small for gestational age (SGA) or appropriate for gestational age (AGA).
Results  IGHD patients born SGA had a significantly higher d3+ frequency (82%) than IGHD patients born AGA (35%, P  = 0·006). Within the group of IGHD patients born SGA, d3 – patients showed a slightly better spontaneous catch up growth before start of GH treatment than d3 + patients (1·1 ± 1·1 SD vs. 0·6 ± 1·1 SDS, P  = 0·040) There was no difference in patients first year's response to GH treatment between GHR d3 + and d3– patients.
Conclusions  In IGHD and MPHD patients, response to GH treatment was independent of GHR genotype. GHR- d3 was significantly more frequent among IGHD patients born SGA. As we are the third to report an association between birth size and GHR d3 status, it is conceivable that the GHR- d3 might affect prenatal growth in IGHD patients by a yet unknown mechanism.     

A biodegradable testosterone microcapsule formulation provides uniform eugonadal levels of testosterone for 10-11 weeks in hypogonadal men.

Limitations of presently available testosterone esters (enanthate and cypionate) include the fluctuating serum testosterone levels and the need for relatively frequent injections (every 10-21 days). These limitations of testosterone esters have prompted the development of more physiological and longer acting systems for androgen delivery. This paper reports pharmacokinetic and pharmacodynamic data with a second generation long-acting testosterone microcapsule formulation in hypogonadal men. This was a single dose, open label, nonrandomized study. Ten hypogonadal men with primary (n = 6) or secondary (n = 4) hypogonadism, otherwise in good health, received 630 mg microencapsulated testosterone in dextran solution (IM) on day 1. Serum total and free testosterone; LH; FSH; dihydrotesterone; estradiol; sex hormone-binding globulin; total cholesterol; high, low, and very low density lipoprotein cholesterol; triglycerides; and apoprotein-AII and -B were measured on multiple occasions during the 2-week control period and the 16-week treatment period. In addition, on days 0, 1, 28, 56, and 84, subjects were hospitalized for detailed hormone analyses over the 24-h period. Serum total and free testosterone levels rose quickly into the midnormal range and stayed uniformly in the eugonadal range for about 70-77 days, after which serum testosterone levels declined gradually into the hypogonadal range. Testosterone release from the microcapsule formulation over the first 10 weeks approximated zero order kinetics. Serum dihydrotestosterone levels rose into the normal range, and testosterone to dihydrotestosterone ratios remained in the physiological range. Serum estradiol levels rose and stayed in the midnormal male range. Serum sex hormone-binding globulin levels decreased significantly during treatment. Serum LH and FSH levels also significantly decreased in the six hypergonadotropic men. Total cholesterol low and very low density lipoprotein cholesterol and triglyceride levels did not change, but plasma high density lipoprotein cholesterol levels decreased significantly during treatment. These data indicate that testosterone microcapsule formulation provides uniform eugonadal levels of testosterone for about 10 weeks. The long duration and zero order kinetics make it an attractive alternative to existing methods of androgen replacement.     

Effect of gender and gonadal status on the long-term response to somatostatin analogue treatment in acromegaly

:GH and IGF-I secretion is related to gender and age. OBJECTIVE: To evaluate the impact of gender and gonadal status on the long-term sensitivity to the somatostatin analogues depot octreotide long-acting release (OCT-LAR) and lanreotide (LAN). PATIENTS: Seventy-three patients with active acromegaly (37 women, median age 34 years; 36 men, median age 38 years) who had not previously been treated with somatostatin analogues were studied: 24 women and 23 men were newly diagnosed; 22 men (61.1%) and 17 women (45.9%) had hypogonadism (P=0.28). Exclusion criteria were age >45 years, follow-up less than 12 months, mixed GH/PRL-secreting adenomas. Study design Observational, analytical, retrospective. Outcome measures (1) Disease control measured as serum GH< 2.5 microg/l and IGF-I normal for age and gender; (2) reduction in tumour volume graded as absent (< 25%), mild (25-50%) and notable (>50%). Results Basal GH, but not IGF-I, levels were higher in women than in men both in the entire series and in 'de novo' patients (97.8+/- 42.2 vs. 71.1+/- 32.6 microg/l, P=0.021). After 12 and 24 months of treatment, respectively, disease control was achieved similarly in men (57.1 and 86.7%) and women (48.6 and 86.7%). Hypogonadal men had longer disease duration than eugonadal men (P=0.022), without any difference in the other parameters. No difference was found between eugonadal and hypogonadal women. Eugonadal men had a smaller tumour volume at baseline than eugonadal women (1396+/- 794 vs. 2896+/- 2871 mm(3), P=0.025). In men undergoing testosterone replacement and withdrawal, there was no change in GH and IGF-I levels after 12 and 24 months of treatment with either LAR or LAN. In the seven women receiving oestro-progestinic replacement, after 24 months of LAR or LAN treatment GH levels were higher during replacement than at withdrawal and IGF-I levels were lower during replacement than withdrawal. Tumour volume decreased significantly in both women and men without any difference between them: the percentage tumour shrinkage in men and women was similar either after 12 (34.4+/-24.4 vs. 40.7+/-22.5%, P=0.38) or 24 months of treatment (58.5+/- 17.4 vs. 56.1+/- 23.6%, P=0.75). Similarly, there was no difference in tumour volume between hypogonadal and eugonadal women and men. CONCLUSIONS: The results of this study demonstrate that long-term responsiveness to OCT-LAR is similar in women and men. Care should be taken in women with acromegaly and hypogonadism treated with somatostatin analogues and oral oestro-progestinic as in this case GH levels are higher while IGF-I levels are lower than after the somatostatin analogues alone.     

Malignant disease and cardiovascular morbidity in hypopituitary adults with or without growth hormone replacement therapy

A retrospective comparison was performed between 1411 hypopituitary adults without GH replacement [mean age, 56.9 (sd 18.6) yr] and the normal population in terms of fatal and nonfatal morbidity. A similar prospective comparison was then made in 289 hypopituitary patients on long-term GH replacement [mean age, 47.6 (sd 14.8) yr; mean duration of GH treatment, 60 months].In the 1411 hypopituitary patients without GH replacement, overall mortality (P < 0.001), and the rates of myocardial infarctions (P < 0.01), cerebrovascular events (P < 0.001), and malignancies (P < 0.001) were increased compared with the normal population. Colorectal cancer was the most common malignancy in this cohort (P < 0.001 vs. the background population). In the 289 hypopituitary patients on GH replacement, overall mortality and the rate of malignancies were similar to the normal population. In the hypopituitary adults on GH therapy, the rate of myocardial infarctions was lower than that in the background population (P < 0.05), and there was a tendency toward an increased rate of cerebrovascular events.In conclusion, overall mortality and the rate of myocardial infarctions were increased in hypopituitary patients without GH replacement. An increased rate of malignancies was observed in the hypopituitary adults without GH therapy, with a predominance of colorectal cancer. GH replacement appeared to provide protection from myocardial infarctions. The rate of cerebrovascular events tended to be increased also in hypopituitary adults on GH therapy.     

Prevalence of low male testosterone levels in primary care in Germany: cross-sectional results from the DETECT study

Objective  Low testosterone levels in men occur with increasing age and are associated with increased morbidity, particularly metabolic syndrome, and mortality. As the prevalence of hypogonadal testosterone levels has not been assessed in the primary care setting in Europe, we aimed to investigate the prevalence of low testosterone levels in this setting, and the patient characteristics and comorbidities associated with this finding.
Design  A cross-sectional, epidemiological study (the Diabetes Cardiovascular Risk-Evaluation: Targets and Essential Data for Commitment of Treatment (DETECT) study).
Patients  A total of 2719 male primary care patients (age 58·7 ± 13·4 years) were included.
Measurements  Testosterone was measured in all patients. Information on diseases, risk conditions and treatments was documented by the primary care physicians. A large set of laboratory parameters was measured in a central laboratory. We calculated univariate and multivariate logistic regression models to assess the associations of low testosterone levels with different health and life style factors.
Results  A total of 19·3% of all men had hypogonadism as defined by testosterone levels < 3·0 ng/ml. Stepwise logistic regression analysis revealed that obesity, metabolic syndrome, cancer, intake of six or more drugs, acute inflammation and nonsmoking were associated with hypogonadal testosterone levels. Higher age, liver diseases, and cancer were associated with very low testosterone levels (< 1·0 ng/ml).
Conclusions  Hypogonadal testosterone levels are common in primary care, particularly in patients with the above conditions.     

The interaction between growth hormone and the thyroid axis in hypopituitary patients

Alterations in the hypothalamo‐pituitary‐thyroid axis have been reported following growth hormone (GH) administration in both adults and children with and without growth hormone deficiency. Reductions in serum free thyroxine (T4), increased tri‐iodothyronine (T3) with or without a reduction in serum thyroid‐stimulating hormone secretion have been reported following GH replacement, but there are wide inconsistencies in the literature about these perturbations. The clinical significance of these changes in thyroid function remains uncertain. Some authors report the changes are transient and revert to normal after a few months or longer. However, in adult hypopituitary patients, GH replacement has been reported to unmask central hypothyroidism biochemically in 36–47% of apparently euthyroid patients, necessitating thyroxine replacement and resulting in an attenuation of the benefit of GH replacement on quality of life in those who became biochemically hypothyroid after GH replacement. The group at highest risk are those with organic pituitary disease or multiple pituitary hormone deficiencies. It is therefore prudent to monitor thyroid function in hypopituitary patients starting GH therapy to identify those who will develop clinical and biochemical features of central hypothyroidism, thus facilitating optimal and timely replacement.     

Effect of vardenafil on endothelial progenitor cells in hypogonadotrophic hypogonadal patients: role of testosterone treatment

Context  Endothelial progenitor cells (EPCs) are bone marrow-derived cells required for endothelial repair. Circulating EPC concentration is low in conditions characterized by endothelial dysfunction but their number can be increased by treatment with phosphodiesterase-5 (PDE5) inhibitors. EPCs are also reduced in hypogonadal men and testosterone (T) treatment restores their concentration.
Objective  To evaluate the relationship between the effect of PDE5 inhibitors and T on EPCs, we analysed the acute effect of vardenafil on the number of EPCs in hypogonadotrophic hypogonadal (HH) patients, before and after T treatment.
Design and setting  A case–control study at a university andrology centre.
Patients  Fifteen HH subjects and 25 aged-matched controls.
Main outcome measures  The number of circulating EPCs and progenitor cells (PCs) in HH patients was evaluated after acute vardenafil administration at baseline and after 6 months of T supplementation.
Results  At baseline, HH men had significantly lower numbers of PCs and EPCs with respect to controls and vardenafil administration had no effect on the number of these cells. After 6 months of T treatment, all HH patients were eugonadal. With respect to baseline, PCs and EPCs were significantly higher and reached the levels observed in controls. Vardenafil administration in HH men at the end of T treatment induced a significant increase in PCs and EPCs in a manner similar to that in controls.
Conclusions  This study showed that normal T levels are necessary to restore the responsiveness of EPCs to PDE5 inhibitors, suggesting that T positively modulates PDE5 in bone marrow.     

Safety of GH replacement in hypopituitary patients with nonirradiated pituitary and peripituitary tumours

Background  Published data suggest that growth hormone replacement (GHR) may be given safely to patients with hypopituitarism consequent upon a pituitary/peripituitary tumour. However, a preponderance of patients treated with external pituitary irradiation were included.
Objective  To assess the safety of GHR in nonirradiated pituitary/peripituitary tumour.
Design  Prospective audit.
Setting  Tertiary university referral centre.
Patients  We imaged prospectively the pituitary glands of 48 patients (18 males; mean age 51·6 years range 21–77) who had adult onset growth hormone deficiency (AO-GHD) after appropriate treatment for a pituitary/peripituitary tumour but who did not receive external pituitary irradiation.
Intervention  All patients were treated with a dose titration regimen of GH to maintain serum IGF-1 between the median and upper end of the age-related reference range. Pituitary surveillance imaging was performed prior to the commencement of GHR, at 6–12 months and then yearly. For patients with secretory tumours, biochemical markers (cortisol and prolactin) were used as evidence of tumour recurrence.
Results  48 patients with median follow up since commencement of GHR was 38 months (range 9–104). Three patients were judged to have an apparent increase in tumour volume and/or marker, although only one was thought to be possibly GH related – a patient with a cystic chromophobe adenoma who demonstrated a marginal increase in residual tumour volume 4 years after commencement of GHR.
Conclusion  These data add to the growing body of evidence for the safety of GHR in hypopituitary patients consequent upon pituitary/peripituitary mass lesions and represents the first reported series in a heterogeneous group of nonirradiated patients.     

Production rates of cortisol in men with hypogonadism

Healthy men have a larger endogenous cortisol production rate (PR) than healthy women. To investigate whether this sex-specific difference is maintained in men with low serum testosterone concentrations the endogenous PRs (2 pm to 6 pm) of testosterone, dihydrotestosterone (DHT), and cortisol were simultaneously determined in 10 hypogonadal men. As expected, hypogonadal men were characterized by subnormal PRs of testosterone (19.6 +/- 5.7 microg/h; normal, 180 to 346 microg/h) and of DHT (1.6 +/- 1.1 microg/h; normal, 11 to 20 microg/h). In hypogonadal patients with an intact pituitary-adrenal axis (n = 8), plasma concentrations (7.3 +/- 1.8 microg/dL), metabolic clearance rates (MCRs) (10.0 +/- 4.6 L/h), and endogenous PRs (0.6 +/- 0.2 mg/h) of cortisol were comparable to those seen in eugonadal men. Hence, the sex-specific difference in endogenous cortisol PRs does not depend on the prevailing serum concentrations and on the endogenous PRs of testosterone.     

Bone mineral density in acromegaly: the effect of gender,disease activity and gonadal status

OBJECTIVE: Data on bone mineral density (BMD) in acromegaly are conflicting as most previous studies collectively evaluated eugonadal and hypogonadal patients of both sexes, with or without active disease. We have evaluated BMD in 152 acromegalic patients of both sexes with varying disease activity and gonadal status. DESIGN: Cross-sectional, retrospective. PATIENTS: We studied 152 acromegalic patients (99 women aged 26-72 years, and 53 men aged 21-75 years), 107 with active and 45 with controlled disease. Eighty-five patients had normal gonadal status and 67 were hypogonadal. MEASUREMENTS: In all patients we measured serum GH levels by immunoenzimometric assay, and serum IGF-I levels by radioimmunoassay. BMD was assessed at spine L2-L4 (LS) and at femoral neck (FN) by dual energy X-ray absorptiometry; results are expressed as Z-values. RESULTS: We evaluated the effect of GH excess on bone at different sites in relation to gonadal status, disease activity and gender. At LS, in respect to the reference population, BMD (mean +/- SE) values were higher in eugonadal patients (active: 0.71 +/- 0.29, P < 0.02; controlled: 0.65 +/- 0.28, P < 0.05) and lower in hypogonadal ones (active: -0.64 +/- 0.35, 0.1 < P < 0.05; controlled: -1.05 +/- 0.36, P < 0.01), regardless of disease activity. On the contrary, at FN, BMD was higher than in the reference population, both in eugonadal (1.01 +/- 0.22, P < 0.001) and hypogonadal (0.63 +/- 0.17, P < 0.001) patients only in subjects with active disease, but not in those in which the disease was controlled (eugonadal: 0.31 +/- 0.23, P = ns; hypogonadal 0.04 +/- 0.28, P = ns). We did not observe any difference in BMD values according to gender both at LS (males vs. females -0.02 +/- 0.30 vs. 0.01 +/- 0.24, P = ns) or at FN (0.77 +/- 0.19 vs. 0.63 +/- 0.15, P = ns). CONCLUSIONS: The anabolic effect of GH excess on bone in acromegalic patients is: (i) gender-independent; (ii) evident at the spine only in eugonadal regardless of disease activity; (iii) evident at femoral neck only in the presence of active disease regardless of gonadal status.     

Glucocorticoid replacement is associated with hypertriglyceridaemia, elevated glucose and higher non-HDL cholesterol and may diminish the association of HDL cholesterol with the -629C>A CETP promoter polymorphism in GH-receiving hypopituitary patients

Objectives The effect of glucocorticoid substitution on the prevalence of metabolic syndrome components (NCEP ATP III criteria) and serum lipid levels was determined in GH‐replaced hypopituitary patients. As glucocorticoid replacement is associated with a pronounced decrease in plasma cholesteryl ester transfer protein (CETP) activity, we also tested associations of HDL cholesterol with the –629C>A CETP promoter polymorphism in subjects with and without ACTH deficiency. Design and patients In a university setting, we retrieved protocolized clinical and laboratory data from 165 adult hypopituitary patients, who had received GH for 1 year. Results After adjustment for age, sex and smoking, non‐HDL cholesterol (P = 0·05) and triglycerides (P = 0·004) were higher, but HDL cholesterol was not decreased in 117 glucocorticoid (mainly cortisone acetate in two divided doses) receiving subjects compared to 48 ACTH‐sufficient subjects. The prevalence of elevated plasma glucose and/or diabetes (P = 0·04) and hypertriglyceridaemia (P = 0·005), but not of other metabolic syndrome components, was higher in glucocorticoid‐replaced subjects. HDL cholesterol was higher in –629 A allele carriers compared to –629CC homozygotes in ACTH‐sufficient subjects (P = 0·04), but not in glucocorticoid‐treated subjects (P = 0·13). Multiple linear regression analysis demonstrated that only in ACTH‐sufficient subjects, HDL cholesterol was independently related to this CETP gene variation (P = 0·03). Conclusions In GH‐ and glucocorticoid‐replaced hypopituitary patients, serum non‐HDL cholesterol and triglycerides are higher and the prevalence of hyperglycaemia is increased, but HDL cholesterol is not decreased. Conventional glucocorticoid replacement appears to diminish the association of HDL cholesterol with a common CETP gene variation.     

Peroxisome proliferator-activated receptor gamma agonism modifies the effects of growth hormone on lipolysis and insulin sensitivity

Context  Peroxisome proliferator-activated receptor gamma (PPAR-γ) agonists such as thiazolidinediones (TZDs) improve insulin sensitivity in type 2 diabetes mellitus (T2DM) through effects on fat metabolism whereas GH stimulates lipolysis and induces insulin resistance.
Objective  To evaluate the impact of TZDs on fat metabolism and insulin sensitivity in subjects exposed to stable GH levels.
Design  A randomized, placebo-controlled, double-blind parallel-group study including 20 GH-deficient patients on continued GH replacement therapy. The patients were studied before and after 12 weeks.
Intervention  Patients received either pioglitazone 30 mg ( N  = 10) or placebo ( N  = 10) once daily for 12 weeks.
Results  Adiponectin levels almost doubled during pioglitazone treatment ( P =  0·0001). Pioglitazone significantly decreased basal free fatty acid (FFA) levels ( P =  0·02) and lipid oxidation ( P =  0·02). Basal glucose oxidation rate ( P =  0·004) and insulin sensitivity ( P =  0·03) improved in the patients who received pioglitazone treatment. The change in insulin-stimulated adiponectin level after pioglitazone treatment was positively correlated to the change in insulin-stimulated total glucose disposal ( R  = 0·69, P  = 0·04).
Conclusion  The impact of GH on lipolysis and insulin sensitivity can be modified by administration of TZDs.